The invention discloses a method for rapidly measuring the chelating rate of a sugar alcohol chelated calcium fertilizer by adopting visible spectrophotometry. The method comprises the steps of firstly, at an oscillation frequency of 100-350r/min, taking acetone as an extracting agent for repeated extraction, and separating chelated calcium and free calcium of sugar alcohol chelated calcium in thesugar alcohol chelated calcium fertilizer, so as to obtain the sugar alcohol chelated calcium and supernate; then, taking a salicylic acid-sulfuric acid solution and NaOH as color developing agents,and at a wavelength of 410nm, measuring the content of nitrates in the sugar alcohol chelated calcium and the supernate by adopting the visible spectrophotometry; and finally, calculating the chelating rate through a formula. According to the method, the measurement of calcium ions is converted into the measurement of the content of nitrate ions, so that the color development is obvious, the measurement is accurate, and the measurement of the content of the calcium ions can be compared; the spectrophotometry experiment has low requirements on equipment and personnel, and is suitable for measurement in enterprise and ordinary laboratories; and the chelating rate can be measured only by calculating the content of the nitrates, and the content of the nitrates does not need to be converted into the content of the calcium ions, so that the calculation process is simplified.